Fibromyalgia and Misdiagnosis

What is fibromyalgia?

Fibromyalgia is a chronic pain syndrome that involves widespread muscle pain (myalgias) and joint pain (arthralgias). Fibromyalgia is thought to be due to central sensitization (CS), which causes chronic pain and pain amplification due to a dysfunction in the way the brain and spinal cord process painful and non-painful signals.

In addition to pain, fibromyalgia is frequently accompanied by additional symptoms, including fatigue, cognitive impairment/brain fog, headaches, depression, anxiety, and insomnia.

Fibromyalgia can be difficult to diagnose due to the following:

• Symptom overlap
  Widespread pain and fatigue are symptoms of various other health conditions.
• Diagnosis of exclusion
  No specific test or scan can definitively diagnose fibromyalgia.
• Coexisting conditions
  Diseases such as lupus and rheumatoid arthritis can cause secondary fibromyalgia. Coexisting diseases can complicate the diagnostic process, especially when symptoms overlap.

Common misdiagnoses

A variety of health conditions are often mistaken for fibromyalgia. These include, but are not limited to, the following:

• Myofascial pain syndrome
  Myofascial pain syndrome is a chronic condition that involves muscle pain. The pain differs from fibromyalgia pain and is more localized. Painful knots in the muscle(s), known as trigger points, are characteristic of myofascial pain syndrome.
• Rheumatic diseases
  Conditions such as rheumatoid arthritis, Sjögren's syndrome, and lupus attack connective tissues. Each of these conditions can cause widespread pain and fatigue.
• Neurological disorders
  Both multiple sclerosis and myasthenia gravis share similar symptoms with fibromyalgia such as numbness, tingling and fatigue, but both of these conditions can be diagnosed objectively using imaging, muscle tests, and nerve studies. Small fiber neuropathy (SFN) can also cause numbness, tingling and pain. However, symptoms of SFN tend to start in the hands and feet.
• Lyme disease
  Lyme disease is a tick-borne illness caused by bacteria. It shares overlapping symptoms of pain, fatigue and cognitive difficulties with fibromyalgia; however, a rash is typically present with Lyme disease.
• Thyroid disease
  Hypothyroidism frequently causes fatigue.
• Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
  Symptoms of chronic fatigue syndrome also include chronic pain and fatigue. However, fatigue is the dominant symptom of CFS.

Symptoms of fibromyalgia

A combination of the following symptoms is more common with fibromyalgia than with other health conditions:

• Diffuse muscle pain (above and below the waist on both sides of the body) not associated with inflammatory characteristics, such as swelling, rashes, or swollen lymph nodes
• Fatigue and sleep disturbances
• Irritable bowel syndrome
• Frequent or painful urination
• Numbness and tingling
• Depression and anxiety
• Cognitive impairment